Thermostatic oven control mechanism



July 14,1931. I A; H. KOHLMEYER ET AL 1,814,002 v THERMOSTATIC OVENCONTROL MECHANISM 2 Sheets-Sheet Original Fled Jan. 23, 1.928

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July 14, 1931.

A. H. KOHLMEYER ET AL.

THERMOSTATIC ov EN CONTROL MECHANI SM Original Filed Jan. 215, 1928 2Sheets-Sheet VMM l 21H50: mtr/Q Patented July 1d, 1.931

UNITED STATES PATENT .l oFFlcEj i Arretrati: H. xonmilnm am) FREDERICKA. xonLMEYEn, on nn'rnom, MTGHTGAN THEBMSTATIC OVEN' CONTRLMECHANISMApplication led January 23,1928, Serial No. 248,588. Renewed ibecember9, 1980.

This invention relates to the ovens of gas stoves, and particularly tomechanisms for controlling in common the ventilation of such ovens andthe delivery -of gas to the burners thereof.

`An object of the present invention is to exercise automatic controlover an ovenventing damper and a valve inthe pipe delivering fuel to theburner of the oven by 'l0 mechanism responding toa single thermostaticmeans.

Another obg'ect is to provide forthe facile adjustment o the temperatureat'whichit takes effect.

Still another object is to reduce a thermostatic oven control mechanismof the described character to a maximum simplicity, to thereby minimizethe original cost and the expense of upkee 90 These and various otherobjects the invention attains by the construction hereinafter describedand illustrated in the accompanying drawings, wherein:

Fi re 1 is a front view of an oven equipped with the improved controlmechamsm.

Figure 2 is a vertical sectional view of the same taken upon the line2-2 of Figure 1. Figure 3 is a horizontal sectional view of said oventaken upon the line 3-3 of Figure 2.

Figure 4 is a rear View of the oven. VFigure 5 is an axial sectionalview of a valve adapted to be thermostatically controlled.

Figure 6 is a detail elevational view of the thermostatic controlmember.

In these views, the reference character 1 designates an loven which mayor may not constitute an integral portion of a gas range.

' Preferably said oven is provided with hollowwalls filled with somesuitable heat insulation such as is indicated at 2. Access is had to theoven by the usual hinged door 3 at the front thereof, said door being normally held closed by a suitable latch 4 as is common practice. It ispreferred to dispose in the lower portion of said oven a perforatedfalse bottom 5 between which and the true bottom of the oven, one ormore burners 6 -it is preferred to slightly space a pair of such amechanism to regulate.

' are mounted. In 'order that the heated air and .gases rising from saidburners in the Vusual manner may be distributed with substantialuniformity within the oven proper,

plates 6a from the side walls of the oven and '-to perforate said platesfor the discharge into the oven of the gases rising between said platesand side walls.

To the burners 6 is connected a gas de? so:

livery pipe 7 and the delivery of gas through said pipe is adapted to becontrolled by the .usual manually operable valve 8.

At the rear of the oven 1 the pipe 7 has an upwardly arched portion inwhich is provided a valve 9 (see Figure 5)A adapted to regulate the flowof fuel responsive to only a slight effort.l As will-presently appear,this valve is under thermostatic control.

Beneath each burner 6 there is formed in the oven bottom one or moreopenings 10 through whichv air may be supp-lied tothe burners 6 tosupport combustion. Preferably baffle plates 1l are secured to the ovenslightly below the openings 10 to minimize the downward radiation ofheat from the burners.-

In the rear wall of the oven, and preferably in the center portion ofsaid wall, there is formed an outlet 12 for air and gases, the sonecessary circulation through the oven being thus established jointly bythe openings l0 and 12. Such ventilation is regulableby a damper 13controlling the opening 12 and hinged to the oven, preferably exteriorlythereof. v A

Describing now a mechanism. for thermostatically controlling the valve 9and damper 13 in common, 14 designates a thermostat disposed within theoven preferably in the top portion thereof, since the maximumtemperatures are encountered in said portion. While said thermostat maybe of various forms, it is preferred to' form this device of avbi-metallic sheet metal plate, utilizing differential co-eflicients ofexpansion of its component metals to cause it to flex proportionately tothe ltemperature to' which it is exposed. One end of said thermostat ishinged upon a bracket l5 carried by the rear wall l.

of the oven and its other end is engaged by a rod 16 which passesthrough a front wall of the oven and carries an actuating crank 17externally adjacent to said wall. The forward end portion of the rod 16is threaded into a feed nut 18 rigidly secured in any suitable mannert'o the front wall'of the oven and preferably set into said wall. Inorder to permit a free swinging of the thermostatic plate 14 about itshinged end responsive to longitudinal adjustment of the rod 16, 1t ispreferred to thread the rear end portion. of said rod and to engage itsthreads by a pair of nuts 19, one at each side of the plate 14, havingtheir opposing faces spherically rounded to permit the desired playbetween said rod and plate. Also the opening 2Oa formed in said memberto receive the rod 16 is slightly elongated to permit of the necessaryflexure of said member.

The mechanism actuable by the thermostat 14 comprises a bell crank 20exteriorly p-ivoted upon the rear wall of the oven and elongatedsubstantially vertically. The actuating connection from the thermostatto said bell crank is established by a pin 21 freely slidable in anopening 22 in the rear oven wall, and engageable at its front end withthe mid portion of the plate 14. An abutment 23 engageable by said pinis carried by a screw 24 threaded in the upper end of the lever 20 andis adjustable to and from said pin. A link 26 establishes a.swingingconnection between the lower end of the lever 20 and the damper13, and it is preferred to provide said link with a series oflongitudinally spaced openings (see Figure 2) to permit its connectionto said lever at various points of its length to thereby regulate thedegree of opening of the damper 13.

To control the valve 9 by the lever 20, the stem 9a of said valvecarries at its forward end an abutment 27 adapted to bear against and beactuated by the lever to close said valve. The open position of thevalve is normally established by a spring 28 coiled upon the stem 9abetween the casing of said Valve and said abutment. A leather diaphragm29 in said casing establishes a seal against leakage of gas.

In the operation of the described mechanism, when the temperature withinthe oven rises beyond a predetermined point, the resulting fiexure ofthe member 14 acts through the pin 21 upon the bell crank 20 to rock theupper end thereof rearwardly so that the consequent forward actuation ofthe lower portion of said lever tends to close the damper 13. Thedescribed actuation of the bell crank further acts through the stem 9aand abutment 27 to shift the valve 9 toward its seat. Thus the flow ofgas to the burners is reduced and the oven temperature is maintained atthe desired minimum.

It is to be understood that the actuation of the valve 9 will in noevent be sufcient to full cut off the delivery of gas to the burner. Iftlsiat were permitted, the subsequent opening of the valve by the.spring 28 would result in escaping gas.

When the construction is originally tested, the screw 23 is adjusted toassure a response of the lever 20 to deflection of the thermostatthrouofh a suitable range. The user of the ovenfliowever, may moredefinitely regulate the thermostatic mechanism by turning the crank 18and thus feeding the rod 16 forwardly and rearwardly to swing thethermostatic member 14 correspondingly. Preferably a suitable arcuatedial piece 30 is asso' ciated with said crank and on said dial piece isindicated by radial markings a series of temperatures which may bemaintained in corresponding positions of adjustment of the crank 17.

Said mechanism is of a relatively simple nature, largely because of theuse of a single thermostat to exercise both of the desired functions offuel control and ventilation control. Because of its simplicity and thefewness of its parts, the mechanism is relatively inexpensive and is notlikely to get out of order.

While it will be apparent that the illustrated embodiment of ourinvention herein disclosed is well calculated to adequately fulfill theobjects and advantages primarily stated, it is to be understood that theinvention is susceptible to variation, modification and change withinthe spirit and scope of the subjoined claims.

What we claim is:

1. In a thermostatic control mechanism, the combination with lan ovenhaving openings for the admission and discharge of air, of a burner forheating said oven, means forv delivering fuel to said burner, a dampercontrolling one of said openings and a valve arranged exteriorly of theoven controlling said fuel delivery, a lever pivoted between its endsupon the oven exteriorly thereof, an actuating connection from saidlever at one side of its pivot to said damper, an actuating connectionfrom said lever at the other side of its pivot to said valve, athermostat within the oven subjected to the heat thereof, and a pinslidable in a wall of the oven transmitting control from said thermostatto said lever.

2. I n a thermostatic control mechanism, the combination with an ovenhaving a vent opening in a wall thereof, of a lever member exteriorlypivoted upon said wall, adamper controlling said opening, means foractuating said damper from one end of said lever, a thermostat withinthe oven subjected to the heat thereof, and a pin slidable in a wall ofthe oven forming an actuating connection to said lever from saidthermostat.

3. In a thermostatic control mechanism, the combination with an oven anda heater for damper controlling said a device Ogni?? controlhngenergization o sai heater, -a

thermostat within the oven, a lever exteriorlypivoted upon theoven,^means for actuating said lever by said thermostat, and directactuating connections fromsaid lever to said damper and control device.

4. In a thermostatic control mechanism, the combination with an ovenhaving an air vent opening in a wall thereof, of a closure for saidopening, a burner for heatin said oven, a valve exteriorl adjacent tosai wall controlling delivery ogfuel to said burner, a lever pivotedupon said wall, a direct actuating connection to said closure from oneend of said lever, a thermostat within said oven, means operating throuh said wall ada ted to actuate the other en of said Alever rom saidthermostat, and means carried by said lever between its ends exercisingcontrol of said valve.

In witness whereof we hereunto set our hands.

AUGUST H. KOHLMEYER. FREDERICK A. KOHLMEYER.

